"Behind the dispute over science is another concern. Political leaders worry that they are being asked to take unacceptable falls in economic growth and living standards to tackle climate change," Mr Blair said.

"If we were to put forward as a solution to climate change something which would involve drastic cuts in economic growth or standards of living, it would not matter how justified it was, it simply would not be agreed to."

His speech appeared designed to win over the US administration, which has refused to sign up to the Kyoto Protocol.

The treaty, which comes into force on 16 February, sets tough international targets for reducing damaging greenhouse gas emissions.

Mr Blair said that Kyoto and the European carbon emissions trading scheme would be a "powerful driver" not just towards sustainable means of energy generation and industrial production but also for new economic opportunities.

Tony Juniper of campaigning group Friends of the Earth welcomed Mr Blair's speech.

"Not only must we see this as an environmental issue, but also as an economic opportunity," he told the BBC.

"You can reduce environmental impact without affecting economic growth. New technologies are coming along all the time."

These included systems that reduced the amount of CO2 that goes into the atmosphere at the point of production.

Observers fear that greenhouse emissions from developing countries will greatly exacerbate the problem as their economies grow.

Some campaigners could see Mr Blair's comments as a watering down of his commitment to use Britain's presidency of the G8 group of industrialised nations to tackle climate change.